These studies are aimed at investigating the absorption and pharmacokinetics of the isoflavones, daidzein, genistein, and their respective glycoside conjugates. These compounds are found in high concentrations in all soy protein products and have been found to have anti-cancer actions. Because of the differences in the composition of isoflavones in soy protein foods, it is important to understand the extent of metabolism and absorption of the individual isoflavones because they differ greatly in chemical behavior.